1. Field of the Invention
The present invention relates generally to hinges, and particularly to a hinge positioning unit.
2. Discussion of the Related Art
Hinges allow two elements to rotate relative to each other. A force or pressure applied to one of the two elements facilitates this relative movement. The hinges may be designed such that the two elements are usually able to remain at the positions reached after the applied force is removed. Many devices such as notebook computers and clamshell mobile phones incorporate such hinges.
A typical hinge used in a device having a liquid crystal display screen includes a first hinge leaf and a second hinge leaf rotatably connected to the first hinge leaf. An elastic member and a plurality of washers are disposed between the first hinge leaf and the second hinge leaf. An elastic force of the elastic member makes the first hinge leaf, the second hinge leaf, and the washers abut to adjacent members. Frictional forces between the members are strong enough to prevent the members from rotating arbitrarily. When a force large enough to overcome the frictional force is imparted on the second hinge leaf, the second hinge leaf can rotate relative to the first hinge leaf.
However, when the frictional force is not strong enough, the second hinge leaf is likely to rotate relative to the first hinge leaf without the application of outside forces and may not remain at a desired position. On the other hand, when the frictional force is too strong, the second hinge leaf may rotate only on applying an excessive amount of force. In addition, when the hinge is used over a certain time, the frictional force may become smaller because of deformation of the elastic member, abrasion of the washers, or other reasons, thus the hinge cannot work.
Therefore, a new hinge positioning structure and unit to solve the above-described problems are desired.